Current supply device for use in electric furnaces

ABSTRACT

Device for supplying current to self-consuming electrodes which are required to be advanced or lowered during operation, for example in an electrothermal reduction furnace. A plurality of current supply means encircling the electrode and spaced apart from each other by small slits is arranged above the furnace head. The individual current supply means are concentrically surrounded by a ring which forces them into elastic contact with the electrode, and are cooled separately.

United States Patent Seifert et al.

[151 3,692,917 [451 Sept. 19,1972

[54] CURRENT SUPPLY DEVICE FOR USE IN ELECTRIC FURNACES [72] Inventors: Helmut Seifert, Hans Werner Stephan, Cologne; Friedrich Wilhelm Dorn, Hermulheim, all of Germany [73I Assignee: Knapsuck Aktiengesellschaft Knupsack bel, Cologne, icrmany [22] Filed: March 23, 1971 211 App]. No.: 127,186

[30] Foreign Application Priority Data March 24, 1970 Germany ..P 20 14 019.6

[52] US. Cl ..l3/15 [51] Int. Cl. ..H05b 7/10 [58] Field of Search ..l3/l4, 15,16

[56] References Cited UNITED STATES PATENTS 2,845,468 7/1958 Haavik ..l3/l4 UX 2,982,804 5/1961 Reschke 13/16 2,753,388 7/1956 Bjerkas ..l3ll6 2,758,145 8/1956 Bjerkas ..l3/l6 Primary Examiner-Roy N. Envall, Jr. Attorney-Connolly & Hutz 5 7 ABSTRACT Device for supplying current to self-consuming elec-' trodes which are required to be advanced or lowered during operation, for example in an electrothermal reduction furnace. A plurality of current supply means encircling the electrode and spaced apart from each other by small slits is arranged above the furnace head. The individual current supply means are concentn'cally surrounded by a ring which forces them into elastic contact with the electrode, and are cooled separately.

2 Claims, 3 Drawing Figures PATENTEDSEP 19 m2 SHEET 1 [1F 3 PATENTEUSEP 19 m2 SHEEI 2 [IF 3 PATENTEU SEP 19. I972 SHEET 3 OF 3 CURRENT SUPPLY DEVICE FOR USE IN ELECTRIC FURNACES The present invention provides a current supply device for use, for example, in electrothermal reduction furnaces fitted with self-consuming electrodes which are required to be advanced or lowered during operation, wherein the current supply means, which may be designed as gripping jaws, are arranged above the furnace head.

In a conventional device of the type described above, a plurality of contact fingers encircling the electrode is arranged within a holding means which has a conical outside and is placed in the furnace head. The contact fingers are spring-mounted in an attempt to effect the transfer of current from the contact fingers to the'elcctrode with a minimum of current loss. While such current transfer device has been found to work reliably up to a certain current strength, the fact remains that this limiting current strength must not be exceeded for thermal reasons because of the lack of cooling systems.

It is accordingly an object of the present invention to provide a device for supplying current of any intensity without the need to limit the strength of the current to be transferred, for thermal reasons. The device of the present invention which has been found fully satisfactory substantially comprises a plurality of individual current supply means, for example gripping jaws, encircling the electrode and spaced apart from each other by means of small slits left therebetween; a ring concentrically surrounding the current supply means and forcing them into elastic contact with the electrode; each of the individual current supply means being cooled separately.

In accordance with a further essential embodiment of the present invention, each of the individual current supply means is formed with a cavity into which projects a twin tube comprising an outer cooling medium inlet tube delivering the cooling medium to the cavity in the current supply means, and an inner cooling medium outlet tube transporting the cooling medium away from the cavity, and inversely. Especially with the use of this embodiment of the present invention is it possible to supply current of high intensity. The preferred cooling medium is water.

In accordance with a still further essential embodiment of the present invention, the overall cooling pipes are arranged so as to form a cage surrounding the electrode concentrically. The cooling pipes are simultaneously used as conductors. Still further, the contact springs bear against an annular ring encircling the current supply means, and are arranged so as to be adjustable from the outside. In this way, the contact pressure is easy to regulate.

The device of the present invention finds use in electrothermal reduction furnaces as well as in plasma burners for the cracking of hydrocarbons to give acetylene, ethylene, methane and hydrogen, and for operation in an electrically heated fluidized bed for the production of metals from ores, or for the production of phosphorus from phosphate, coke and quartz, for example.

An exemplary embodiment of the present invention is shown diagrammatically in the accompanying drawing. The invention is not limited to the embodiment exemplified. It admits of various modifications without departing from its scope.

With reference to the accompanying drawing:

FIG. 1 is a side elevational view of the electrode within the range of the current supply means,

FIG. 2 is a cross-sectional view taken along line ll-Il of FIG. 1, and

FIG. 3 is a cross-sectional view taken along line III- III of FIG. 1.

The device of the present invention which is shown diagrammatically in the accompanying drawing is used for supplying current to self-consuming electrodes that are required to be advanced or lowered during operation and used, for example, in electrothermal reduction furnaces, electrically heated fluidized bed furnaces for the production of metals from ores, or plasma burners for the cracking of hydrocarbons to give acetylene, ethylene, methane and hydrogen. As can be seen, the current supply means 10, which may be designed as gripping jaws, are arranged above furnace head 11. Directly mounted on furnace head 11 is a flange 12 to which is secured a lantern 13. Lantern 13 encapsulates a plurality of current supply means 10, which are spaced apart from each other by means of small slits 14 left therebetween, and encircle electrode 15 (this is shown in FIG. 3). The current supply means 10 are spring-mounted on springs 16 which bear against annular ring 17 concentrically surrounding the current supply means 10 and forcing them into elastic contact with the electrode.

Each of the individual current supply means 10 is formed with a cavity 18 into which projects a twin tube 19, 20. The twin tube comprises an outer tube 19 delivering cooling medium to cavity 18, and an inner tube 20 transporting the cooling medium away from cavity 18. The direction of flow of the cooling medium may be inversed, if necessary or convenient.

The overall cooling pipes 19 and 20 are arranged so as to form a cage concentrically encircling electrode 15 (this is shown in FIG. 2). In addition to conveying the cooling medium, the cooling pipes are used as conductors. To this end, they are electrically connected, preferably welded, to current junction lug 21. Contact springs 16 are adjustable from the outside by means of bolts 22 through apertures formed in lantern 13.

The electrode is moved forward, i.e., lowered in the furnace, by means of two profiled friction rollers 23, which are rotatably secured to a roller frame (not shown in the drawing).

As can be seen from FIG. 2, all of the cooling pipes forming the pipe cage are bent away from the electrode approximately at the level of line II-II, i.e., one half thereof is bent away from one side of the electrode, and the other half is bent away from the other side of the electrode, and the two halves are united together (in a manner not shown in the drawing) at some distance from the electrode.

We claim:

I. A current supply device for use in electric furnaces fitted with self consuming electrodes which are required to be advanced during operation, the device comprising a plurality of individual current supply jaws encircling the electrode, the jaws being spaced apart from each other by means of small slits left therebetween and being mounted above the furnace head, each of the individual current supply jaws having a cavity, a pair of tubes connected to each of the jaws in communication with each of the cavities for circulating a cooling medium through each of the cavities assprings being constructed and arranged to force the current supply jaws into elastic contact with the electrode, and all of the pairs of tubes being arranged so as to form a pipe cage concentrically surrounding the 5 electrode.

2. A current supply device as set forth in claim 1, wherein each of the pairs of tubes comprises a coaxial pair of the tubes. 

1. A current supply device for use in electric furnaces fitted with self consuming electrodes which are required to be advanced during operation, the device comprising a plurality of individual current supply jaws encircling the electrode, the jaws being spaced apart from each other by means of small slits left therebetween and being mounted above the furnace head, each of the individual current supply jaws having a cavity, a pair of tubes connected to each of the jaws in communication with each of the cavities for circulating a cooling medium through each of the cavities associated with each of the individual jaws, a current supply junction on the device, each of the pairs of tube being electrically connected to the current supply junction to cause them to conduct electrical current, an annular pressure ring concentrically surrounding the current suppLy jaws, contact springs arranged between each of the current supply jaws and the annular pressure ring, external adjusting elements connected to the contact springs for varying their force, the contact springs being constructed and arranged to force the current supply jaws into elastic contact with the electrode, and all of the pairs of tubes being arranged so as to form a pipe cage concentrically surrounding the electrode.
 2. A current supply device as set forth in claim 1, wherein each of the pairs of tubes comprises a coaxial pair of the tubes. 